The mechanism and parameters of P element-mediated gene transfer will be examined. Methods of DNA introduction into Drosophila embryos will be optimized. The influence of the size and structure of the DNA to be transferred will be studied. Alternative hypotheses for the observed non-random distribution of chromosomal insertion sites will be tested. Improved gene transfer vectors will be constructed and characterized. The possible uses of P element-mediated gene transfer in other cell types and organisms will also be explored. Efficient methods for the controlled transfer of genetic information into germline cells of metazoans are of central importance in analyzing the regulatory properties which govern the development of these organisms. Knowledge of such regulatory processes are essential to understanding the etiology of birth defects, aging and acquired disease.